Re: [PATCH v7 13/13] pack-objects: reorder members to shrink struct object_entry

From: Duy Nguyen <pclouds@gmail.com>
Date: Mar 31, 2018, 04:10 UTC
Message-ID: <CACsJy8Cr=uN8d9ZWO=xbyOYbMmS6V3FCdw_tww15d6NHpLMTag@mail.gmail.com>
In-Reply-To: <20180330212656.GK14782@sigill.intra.peff.net>

On Fri, Mar 30, 2018 at 11:26 PM, Jeff King <peff@peff.net> wrote:

Show 10 quoted lines

> On Sat, Mar 24, 2018 at 07:33:53AM +0100, Nguyễn Thái Ngọc Duy wrote:
>
>> Previous patches leave lots of holes and padding in this struct. This
>> patch reorders the members and shrinks the struct down to 80 bytes
>> (from 136 bytes, before any field shrinking is done) with 16 bits to
>> spare (and a couple more in in_pack_header_size when we really run out
>> of bits).
>
> Out of curiosity, did you count this yourself, or did you double-check
> with a few compilers to make sure they all produce the same result?

I used pahole though only with .o files created by gcc 64-bit. I'll try the 32-bit version and clang as well.

-- 
Duy